Shallow-water flow past isolated topography. Part I: vorticity production and wake formation

Abstract

High-resolution numerical simulations are utilized to construct a regime diagram for steady left-right symmetric flow and for the domain of parameter space with subcritical upstream conditions. Three distinct regimes occur. They are characterized, respectively, by fore-aft symmetry, essentially inviscid dynamics, and entirely subcritical conditions (regime I); by transition to supercritical flow and the occurrence of a hydraulic jump over the lee slope (regime II); and by the inability of the flow to climb the mountain top resulting in flow separation (regime III). Regimes II and III are associated with a wake that entails significant potential vorticity features and sometimes reversed flow. -from Authors